Women with chest pain who undergo noninvasive testing in order to determine etiology of their pain are found to have a high incidence of "false positive" responses, i.e., results suggestive of inducible myocardial ischemia in the absence of angiographic evidence of coronary artery disease. In order to assess the significance of "false positive" noninvasive testing in women with chest pain and normal coronary angiograms, 26 women < 60 years of age with chest pain, normal coronary angiograms and normal resting left ventricular function underwent radionuclide angiographic assessment of left ventricular function during graded supine bicycle ergometry and exercise thallium scintigraphy using the Standard Bruce Protocol. Nine women had abnormal exercise left ventricular function (left ventricular ejection fraction decreased or wall motion abnormalities were detected during exercise) and 17 women had normal exercise left ventricular function. Six of 9 (67%) women with abnormal exercise left ventricular function had reversible defects by thallium scintigraphy, compared to only 1 of 17 (6%) women with normal exercise left ventricular function (p<0.003). There was no correlation between the exercise EKG or fixed thallium defects and exercise left ventricular function. Thus, abnormal left ventricular functional responses to exercise in women with chest pain and normal coronary angiograms are commonly associated with evidence of abnormal myocardial perfusion, most likely representing abnormal coronary microvascular function during stress.